protected override void PreFilterProperties(IDictionary properties)
        {
            base.PreFilterProperties(properties);
            object corrRefProperty = properties["CorrelationToken"];
            HandleExternalEventActivity activity = base.Activity as HandleExternalEventActivity;

            this.AddRemoveCorrelationToken(activity.InterfaceType, properties, corrRefProperty);
            Type interfaceType = activity.InterfaceType;

            if (interfaceType != null)
            {
                this.AddRemoveCorrelationToken(interfaceType, properties, corrRefProperty);
                activity.GetParameterPropertyDescriptors(properties);
            }
        }
        protected override void PreFilterProperties(IDictionary properties)
        {
            base.PreFilterProperties(properties);

            object corrRefProperty = properties["CorrelationToken"];

            HandleExternalEventActivity eventSink = Activity as HandleExternalEventActivity;

            AddRemoveCorrelationToken(eventSink.InterfaceType, properties, corrRefProperty);

            Type type = eventSink.InterfaceType;

            if (type == null)
            {
                return;
            }

            AddRemoveCorrelationToken(type, properties, corrRefProperty);

            eventSink.GetParameterPropertyDescriptors(properties);
        }